is the rest still ok? i have a graco infant seat that is about 2 yrs old. our new baby is 2 wks, and i noticed cracks in the buckle part last wk. you know the plastic over the metal parts that click in the big buckle part. so i ordered a new harness assembly, but i wonder about the rest of the seat. it's never been in a crash so I'm just confused..... any ideas???? We live in the mohave desert, so it is very very hot. could it be heat related?? I just wonder if I need a new seat, and don't know what else to look for in terms of wear/heat damage.